Biometric recognition systems are used for authenticating and/or verifying users of devices incorporating the recognition systems. Biometric sensing technology provides a reliable, non-intrusive way to verify individual identity for recognition purposes.
Fingerprints, like various other biometric characteristics, are based on unalterable personal characteristics and thus are a reliable mechanism to identify an individual. There are many potential applications for utilization of fingerprint sensors. For example, fingerprint sensors may be used to provide access control in stationary applications, such as security checkpoints. Electronic fingerprint sensors may also be used to provide access control in portable applications, such as portable computers, personal data assistants (PDAs), cell phones, gaming devices, navigation devices, information appliances, data storage devices, and the like. Accordingly, some applications, in particular applications related to portable devices, may require recognition systems that are both small in size and highly reliable.
Sometimes, the sensor may only be large enough to capture a partial view of the biometric sample being sensed. For example, a partial fingerprint sensor will only be large enough to capture a partial image of a user's fingerprint. This can present several challenges when attempting to reliably recognize the pattern against a stored enrollment template using only the partial view. For one, this partial view provides less discriminative information for the matching system to utilize when attempting to reliably recognize the fingerprint against a stored enrollment template. Additionally, system may need to account for the user presenting different portions of the same fingerprint in different match attempts.
An enrollment template derived from multiple views of the enrolled fingerprint provides a possible solution, but attempting to perform matching between a candidate verification view and a larger enrollment template that is derived from multiple enrollment views is a challenging task.
One possible solution is to stitch together the multiple enrollment views into a single larger view. However, achieving a perfect alignment between the views is often not feasible, and inaccuracies in these alignments can produce distortions at boundaries and overlapping regions between the views that can detrimentally impact match performance.
Another possible solution is to store the enrollment views separately in the enrolled template, and compute individual match scores with each of the views separately. The overall score between the templates can then be based on a summation or other simple combination of the scores to the individual views. Geometric relationships between the enrollment views can be used to constrain the alignments from the verify view to each enrollment view in order to simplify the computation of each individual match score. However, this can cause false results because the overall score is a function of match scores to only the individual views. For example, the combination of individual scores can cause a false match when an imposter matches strongly with only a single view or small subset of views, and conversely, the combination of individual scores can cause a false non-match when a true user matches only weakly with several of the views.
In view of the above, there is a need for a recognition system that can provide a highly reliable recognition process based on a partial view or views of a user's fingerprint. Embodiments of the disclosure provide such a highly reliable recognition system for performing a recognition process based on the partial view or views of the user's fingerprint. These and other advantages of the disclosure, as well as additional inventive features, will be apparent from the description of the disclosure provided herein.